Capacitor switching contactor

ABSTRACT

A capacitor switching contactor is described which includes a standard contactor, an auxiliary switch, an input terminal block, an output terminal block, as well as resistance wires disposed between the terminal blocks, on the one hand, and the auxiliary switch, on the other hand. The resistance wires are connected to connecting terminals in chambers of the terminal blocks, and largely accommodated in the housing of the terminal blocks.

FIELD OF THE INVENTION

The present invention relates to a capacitor switching contactor whichhas a standard contactor having main contacts, an auxiliary switchhaving auxiliary contacts which lead with respect to the main contacts,at least one resistance wire being connected in series each of theauxiliary contacts. The series connection of, in each case, oneauxiliary contact and at least one resistance wire is connected on aphase by phase basis, in parallel, to one main contact, respectively.The contactor has input and output terminals for electrically couplingthe series connections to the main contacts.

BACKGROUND INFORMATION

Capacitor switching contactors are generally known. FIG. 6 shows thefundamental electrical circuit of a capacitor switching contactor K. Inthis context, leading auxiliary contacts VK of an auxiliary switch areconnected in parallel with main contacts HK of a standard contactor. Theconnecting leads from auxiliary contacts VK to main contacts HK aredesigned as resistance wires having the resistance R_(v). In thiscontext, individual input terminals 1,3,5 and individual outputterminals 2,4,6 are used to connect the main conductors to the standardcontactor and to couple the resistance wires. When a capacitor load 7 isswitched in via the capacitor switching contactor according to FIG. 6,the leading auxiliary contacts VK of the auxiliary switch are firstclosed, thereby limiting the short-circuit type current inrush throughresistors R_(v) in this current path. The main contacts HK are thenclosed only after a time delay.

Usually, the resistance wires are run loosely in a plurality of loopsaccording to the length required for the resistance value, and the endsare connected to the individual input terminals and individual outputterminals.

German Patent No. 31 05 117 describes an electromagnetic switchingdevice having main and leading contacts which are interconnected withdamping series resistors in response to capacitive load. On the outgoingcircuit side of main and leading contacts 2 and 3, respectively,resistors 14 are clamped with their ends into the terminals of one mainand one leading contact, respectively. The resistors are formed as wirewraps and have an insulated design, and are each located between twodividing ribs of the housing, protected from external influences.

French Patent No. 27 35 279 describes a switching device having acovering, on whose inner side, flat resistance material is laid in ameander form.

Moreover, German Patent No. 92 00 344 describes an attachment housinghaving components to facilitate mounting on an electrical device havingconnecting terminals, preferably a contactor. The electrical componentsare used to interconnect an operating coil. A flexible connecting leadis provided for connecting the components to a coil terminal.

SUMMARY

An object of the present invention is to provide a capacitor switchingcontactor which is simple in design and renders possible a simple andfast assembly. The objective is achieved by combining the inputterminals and the output terminals into one input terminal block and oneoutput terminal block, respectively, having a housing with chamberswhich are insulated from one another in each case, disposed in which ineach case is a connecting terminal that is electrically connected to aresistance wire, which is brought out from the housing of the inputterminal block or output terminal block, respectively, to be connectedto the auxiliary switch, and whose remaining length is accommodated inthe housing.

This facilitates the assembly, since, instead of a plurality ofindividual input terminals and individual output terminals, terminalblocks may be coupled and connected to the standard contactor. Severalnot easily manipulable individual parts are replaced by oneintrinsically stable connecting block, which, in addition to theconnecting terminals, also accommodates the resistance wires. As aresult, the resistance wires from the housing of the connecting blockcan be connected to the auxiliary switch without forming loops, i.e.,the need is eliminated for the loops, which are a hindrance duringassembly.

It is particularly advantageous for the resistance wire in the housingof the input terminal block or output terminal block to be accommodatedin the same chamber as the connecting terminal that is electricallyconnected to it. In this specific embodiment, the difference inpotential between the resistance wire and the connecting terminalelectrically connected to it is relatively low in comparison withneighboring connecting terminals. In addition, the electrical stress,thus the probability of a short circuit, is kept at a minimum by themutual insulation of the chambers. A further advantageous embodimentprovides for designing the auxiliary switch, together with the input andoutput terminal blocks connected thereto via the resistance wires, as asubassembly, which is able to be coupled electrically and mechanicallyto the standard contactor. A subassembly of this kind is able to becoupled electrically and mechanically to the standard contactor, withlittle manipulation, i.e. the outlay for assembly is quite minimal.Incorrect connections and wiring are virtually ruled out.

It also proves to be especially expedient for the connecting terminalsto be designed with a terminal area for conductor cross sections of upto 70 mm² and, in addition, with a terminal for connecting conductorcross sections of up to 2.5 mm², enabling an auxiliary conductor to beconnected, in addition to the main conductor.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a sub-assembly for a capacitor switching contactor, thesubassembly being composed of an auxiliary switch, an input terminalblock, an output terminal block, and resistance wires according to anexample embodiment of the present invention.

FIG. 2 shows the rear view of an input terminal block or an outputterminal block, respectively.

FIG. 3 shows a perspective view of an input terminal block or outputterminal block, respectively, including the entire connecting terminaland the resistance wire attached thereto.

FIG. 4 shows the view of a complete capacitor switching contactoraccording to the example embodiment of the present invention.

FIG. 5 shows a standard contactor having a terminal block for auxiliaryconductor connection.

FIG. 6 shows the basic circuit diagram of a capacitor switchingcontactor.

DETAILED DESCRIPTION

FIG. 1 illustrates a subassembly 15 made up of an auxiliary switch 11,an input terminal block 12, an output terminal block 13, and resistancewires 14 interconnecting them. A capacitor switching contactor 17according to FIG. 4 is obtained by mechanically and electricallyconnecting this subassembly 15 to a standard contactor 16.

FIG. 2 shows an input terminal block 12 or an output terminal block 13,respectively, as is used in subassembly 15 according to FIG. 1. Theterminal block contains a housing 18 having three chambers 19, which areinsulated from one another, are open to the bottom, and in each of isdisposed a connecting terminal 20, as well as a resistance wire 14electrically connected thereto.

Resistance wires 14 have a length that is appropriate for the desiredresistance value. The resistance wires 14 are brought out of an opening21 in the top side of housing 18, with the length required forconnection to auxiliary switches 11. The remaining length of resistancewire 14 is run in loops in the same chamber 19 as connecting terminal 20that is connected to the resistance wire. In accordance with FIG. 3,connecting terminals 20 are each formed in their lower region as clips22 and, in their upper region, as contact clips 23 having a combinationscrew 24 that is accessible via a hole 25 at the top side of housing 18.Resistance wire 14 is electrically connected to contact clip 23 byattaching the end of resistance wire 14, which is provided with a cablelug 26, to contact clip 23. Contact clips 23 are used to connectauxiliary conductors having a conductor cross-section of up to 2.5 mm².For this, the input terminal block and the output terminal block,respectively, have entry slots 27 at their front ends (see FIG. 1). Mainconductors having a cross section of up to 70 mm² are able to beconnected over the area formed as clip 22. The oblong extensionprolongation 28 of clip 22, projecting out on the rear side of terminalblock 12, 13, is used, in conjunction with the main conductors, for theconnection to standard contactor 16.

FIG. 4 depicts the complete capacitor switching contactor 17 accordingto the present invention, where subassembly 15 is mounted on standardcontactor 16. Of the four auxiliary contacts of auxiliary switch 11,three are used for the leading auxiliary contact functions of capacitorswitching contactor 17, the fourth is not assigned. Input terminal block12 and output terminal block 13 are coupled via fastening segments 29(see FIGS. 2,3) which engage with slots (not shown here) in the sidewalls of standard contactor 16. Subjacent coil terminals 31 can beaccessed by screwdriver via two through-holes 30 in input terminal block12 and output terminal block 13, respectively.

FIG. 5 shows a standard contactor 16 having a side-mounted terminalblock 32 which, besides the main conductor connection, also makespossible the auxiliary conductor connection. The design set-up includinga housing having three chambers and the connecting terminals correspondsto that of input terminal block 12 and output terminal block 13,respectively. Since the need is eliminated for resistance wires,terminal block 32 is narrower in design, no provision being made eitherfor through-holes 30 to access coil terminals 31.

What is claimed is:
 1. A capacitor switching contactor, comprising: acontactor including main contacts; resistance wires; an auxiliary switchincluding auxiliary contacts which lead with respect to the maincontacts, each of the auxiliary contacts being connected in series to arespective one of the resistance wires to form a series combination,each series combination being connected, on a phase by phase basis, inparallel with a respective one of the main contacts; and an inputterminal block and an output terminal block, each of the input terminalblock and the output terminal block including a respective housinghaving chambers, the chambers being insulated from one another, each ofthe chambers having a connecting terminal disposed therein, theconnecting terminal being connected to one of the resistance wiresbrought out from the respective housing of one of the input terminalblock and the output terminal block to be connected to the auxiliaryswitch, a length of the one of the resistance wires being accommodatedin the respective housing of the one of the input terminal block and theoutput terminal, the input terminal block and the output terminal blockelectrically connecting each series combination to the main contacts. 2.The capacitor switching contactor according to claim 1, wherein thelength of the one of the resistance wires is accommodated in a same oneof the chambers as the connecting terminal to which the one of theresistance wires is connected.
 3. The capacitor switching contactoraccording to claim 2, wherein the auxiliary switch, together with theinput terminal block and the output terminal block connected thereto viathe resistance wires is designed as a subassembly, the subassemblyconfigured to couple electrically and mechanically to the contactor. 4.The capacitor switching contactor according to claim 1, wherein eachconnecting terminal has a terminal area for conductor cross-sections ofup to 70 mm² and includes a contact terminal for connecting conductorcross-sections of up to 2.5 mm².